Adaptor for mounting conventional through type current transformers on flat spade terminals

ABSTRACT

A grooved adaptor, two of which may be mounted by means of spring clips inside the window of a conventional through-type current transformer to permit the transformer to be mounted on a flat spade-type terminal for current metering. The adaptors have grooves therein which are opposite to each other when the adaptors are properly positioned in the window of the transformer. The grooves receive opposite edges of the flat spade terminal. The grooves have flexible ribs or teeth extending thereinto which may be removed to permit the grooves to receive spade-terminals of different thicknesses.

United States Patent [191 Smith June 26, 1973 ADAPTOR FOR MOUNTING CONVENTIONAL THROUGH-TYPE CURRENT TRANSFORMERS ON FLAT SPADE TERMINALS [75] Inventor: James E. Smith, Masury, Ohio [73] Assignee: Westinghouse Electric Corporation,

Pittsburgh, Pa.

[22] Filed: Oct. 12, 1971 [21] Appl. No.: 188,302

[52] US. Cl 336/65, 336/174, 336/198 [51] Int. Cl 1101f 15/02, 1101f 27/30 [58] Field of Search 336/173, 174, 175,

[56] References Cited UNITED STATES PATENTS 2/1966 Joseph 174/153 G Rueger 174/153 G X 3,325,591 6/1967 Wahl 174/138 F 3,231,300 1/1966 Moroney 174/153 G X 3,582,852 6/1971 Stetson et a1. 336/208 Primary Examiner-Thomas J. Kozma Attorney-A. T. Stratton and F. E. Browder et a1.

[57] ABSTRACT A grooved adaptor, two of which may be mounted by means of spring clips inside the window of a conventional through-type current transformer to permit the transformer to be mounted on a flat spade-type terminal for current metering. The adaptors have grooves therein which are opposite to each other when the adaptors are properly positioned in the window of the transformer. The grooves receive opposite edges of the flat spade terminal. The grooves have flexible ribs or teeth extending thereinto which may be removed to permit the grooves to receive spade-terminals of different thicknesses.

5 Claims, 6 Drawing Figures PAIENIEnJms ma 3.742.41 0

' sum 1 or 2 ADAPTOR FOR MOUNTING CONVENTIONAL THROUGH-TYPE CURRENT TRANSFORMERS ON FLAT SPADE TERMINALS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to through-type current transformers used for current metering, and particularly to an adaptor which permits modifying the window of a current transformer designed for mounting on rectangular, or round bus bars or bushings for easily mounting on flat spade-type terminals.

2. Description of the Prior Art In the prior art, current transformers of the throughtype design have been provided for mounting on rectangular or round bus bars or terminals for metering current. Auxiliary adaptors have also been cemented into' the windows of conventional through-type transformers for adapting a through-type transformer for mounting on spade-type terminals for metering current. Although adaptors have been provided for mounting conventional through-type transformers on spade terminals, the prior art does not teach the provision of adaptors for the window of a conventional through-type transformer which may be readily inserted into or removed from the window of the transformer in the field for adapting the transformer for mounting upon spadetype terminals. Neither has the prior art provided an adaptor which may be readily modified in the field for mounting on spade terminals of different thicknesses.

Accordingly, it is a main object of this invention to provide an adaptor which may be inserted into the window of a through-type current transformer in the field and held in position by spring clips which engage the casing of the through-type transformer adjacent the window opening. It is also an object to provide an adaptor which may be readily modified in the field to receive spade-terminals of different thicknesses.

SUMMARY OF THE INVENTION This invention provides an adaptor which may be applied to the window of a through-type current transformer which permits the transformer to be readily mounted on a spade terminal for metering current passing through the terminal. The through-type current transformer usually has a rectangular or round window therein for mounting on rectangular or round bus bars or bushings for metering current passing through the bus bars. This invention provides an adaptor comprising a pair of spring clips molded or cast into a body member. The body member may be molded or cast of butyl rubber, or any of the suitable resins, or other suitable material. The spring clips are spaced from each other approximately the thickness of the transformer casing. Each of the spring clips has a pair of hook portions provided therein so that when the adaptor is placed in the window of the transformer, the hooks on the spring clips dig into the casing of the transformer and hold the adaptors firmly in place. Each of the adaptors has a groove therein wide enough to receive the spade terminal. Each of the grooves also has a plurality of oppositely disposed projections or teeth therein which tend to grip the spade terminal. Two of the adaptors are placed in the window of the transformer opposite each other with the grooves in each of the adaptors facing each other. The transformer is mounted on the spade terminal by merely placing the flat spade terminal in the oppositely faced grooves and pushing the transformer down onto the spade.

The adaptors may be adjusted in the field for receiving spade terminals of different thicknesses. With the adaptor unmodified that is, with all of the projections or teeth in the grooves the adaptor will receive one thickness of spade terminal. However, if it is desired to modify the adaptor so that the transformer may be installed on another thickness of spade terminal, the installer merely removes the teeth from the corresponding side of the grooves in each of the adaptors. This will increase the thickness of spade terminal which the adaptors will receive by approximately oneeighth of an inch. If it is desired to install the transformer on a spade terminal of a greater thickness, the installer removes the teeth or projections for the respective other sides of each of the grooves in the two adaptors, and then the adaptor will receive a spade terminal of approximately one-eighth of an inch thicker than the previous spade terminal.

The adaptors may be installed in the field merely by inserting the adaptors in the window of the transformer with the spring clips gripping the sides of the transformer casing. The adaptors may be readily removed from the window of the transformer in the field by prying up on one of the clips with a screwdriver or other tool and sliding the adaptor out of the window of the transformer.

BRIEF DESCRIPTION OF THE DRAWINGS Throughout the description which follows, like refer ence characters refer to like parts in all Figures of the drawing.

FIG. I is a perspective view of a through-type current transformer adapted for mounting on a rectangular bus bar or terminal for metering current.

FIG. 2 is a perspective view of one of the adaptors provided by this invention for insertion into the window of a transformer, such as shown in FIG. 1, for adapting the transformer for mounting on a flat spade-type terminal.

FIG. 3 is a perspective view of the transformer of FIG. 1 with two of the adaptors shown in FIG. 2 mounted in the window of the transformer.

FIG. 4 is a perspective view of a bushing having a spade-type terminal extending therefrom with the transformer of FIG. 3, with two adaptors mounted therein, mounted on the spade terminal.

FIG. 5 is a partial view of the adaptor of FIG. 1 showing the modification for mounting on a spade terminal of a different thickness; and,

FIG. 6 is a partial perspective view of the adaptor of FIG. 5 showing the adaptor modified for mounting on a spade terminal of a still greater thickness.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings in detail, and FIG. 1 in particular, this figure shows a perspective view of a through-type current transformer 10 having a rectangular window 12 therein. The transformer 10 has opposite, substantially parallel, side walls 11 and 13. The transformer 10 is usually mounted on rectangular or round bus bars or terminals to meter current flowing in the bus bars of terminals. The transformer 10 comprises a magnetic core having a winding thereon. The winding is brought out to a pair of terminals 14 which are used for connecting the transformer to the metering apparatus.

FIG. 2 is a perspective view of an adaptor l6 provided by this invention which is used for adapting the transformer of FIG. 1 for easy installation on a flat spade-type terminal 32 for metering the current flowing in the terminal. The adaptor 16 of FIG. 2 comprises a body portion 18 which is molded or cast from butyl rubber, or some suitable resin or other moldable or castable material. The body member 18 has a pair of spaced spring clips 20 and 22 molded therein. The spring clips are spaced from each other approximately the distance of the thickness of the casing of the transformer 10, that is, the distance between the side walls 11 and 13. Each of the spring clips 20 and 22 have a pair of hook members 24 provided therein. The adaptor member 16 also has a vertical groove or slot 26 provided therein. The lower end of the groove 26 has provided integrally therewith a plurality of ribs or teeth 28. The ribs or teeth 28 may be directed upwardly, downwardly, or transverse to the groove or slot 26. As shown in FIG. 2, the width of the groove 30 or slot 26 is approximately one-half inch and the length of each of the ribs or teeth 28 is approximately one-eighth inch. With all of the ribs or teeth 28 intact, as shown in FIG. 2, the groove 26 in the adaptor is intended to receive a spade terminal approximately one-fourth inch thick. However, if it is desired to install the transformer on a spade terminal three-eighths inch thick, the field installer merely removes the teeth or ribs 28 from one side of the groove 26 as shown in FIG. 5. This will increase the width of the bottom part of the slot 26 to approximately three-eighths of an inch. Then the slot 26 will receive a spade terminal three-eighthsof an inch thick. However, if it is desired to install the adaptor 16 on a still thicker spade terminal, the field installer then removes the ribs or teeth 28 from the other side of the groove or slot 26, as shown in FIG. 6, and then the groove 26 will receive a spade terminal of approximately one-half inch thickv To adapt the transformer of FIG. 1, for mounting on a flat spade terminal 32 a pair of the adaptors 16 are inserted into the window 12 of the transformer as shown in FIG. 3. With the adaptors 16 installed as shown in FIG. 3, the hook portions 24 will dig into the side walls 1 l and 13 of the casing of the transformer 10, which is made of rubber or some suitable resin or other suitable material, and firmly hold the adaptors 16 in the window 12 of the transformer 10. In case it is desired to remove the adaptors 16 from the window 12 of the transformer 10 it is merely necessary to pry up on the portions of the spring clips 20 which carry the hooks 24 and slide the spring clips 20 off the side walls ill and E3 of the transformer casing and remove the adaptors l6 from the window 12 of the transformer Ill). If desired, the adaptors 16 may be inserted into the window l2 reversed from the position shown in FIG. 1; that is within the portion of the adaptor 16 having the ribs 28 nearest the top of the spade terminal 32. This will permit the transformer to be pushed further down onto the spade terminal 32.

FIG. 4 illustrates a transformer 10 having a window 12 with a pair of the adaptors 16 mounted in the window 12 of the transformer 10. The transformer is mounted on a flat spade terminal 32 which extends from a bushing 34. The bushing 34 is usually mounted on electrical apparatus and the spade terminal 32 is connected through the bushing 34 to the electrical apparatus in the casing. With the transformer 10 in position upon the spade terminal 32, as shown in FIG. 4, the transformer may be used for metering the current flowing through thespade terminal 32.

As shown in FIG. 4 the slots 26 of the adaptors 16 contain all of the teeth or ribs 28. However, if it is desired to mount the transformer 10 on a thicker spade terminal 32, the ribs or teeth 28 would be removed from one side of each of the slots 26 in each of adaptors 16 such as illustrated in FIG. 5. This would increase the thickness of spade 32 which the adaptor would fit by approximately one-eighth of an inch. However, if it is desired to mount the transformer 10 on a still thicker spade terminal 32, the ribs or teeth 28 would be removed from both sides of the slots 26, as shown in FIG. 6. This would increase the thickness of spade 32 which the adaptor would fit by approximately one-fourth of an inch.

The ribs or teeth 26 may be readily removed in the field, by the installer, by means of a knife or rasp or any other suitable cutting tool.

The transformer shown in FIGS. 1, 2 and 3 usually comprises a laminated metal core 36 having a winding 38 thereon with a protective casing 40, comprised of butyl rubber or a suitable resin, or some other material cast around the corewinding assembly to provide a protective casing for the transformer 10. The terminals 24 are brought out of the casing 40 for connecting the transformer to a metering circuit. The casing has a pair of substantially parallel side walls 11 and 13, and a four sided edge wall 15. The window 12 is defined by a four sided inner edge wall 17.

From the foregoing description taken with the drawings, it' isseen that this invention has provided a simple adaptor which may be applied in the field to adapt a transformer for installation on flat spade type terminals of different thickness. The adaptors may be applied to the window of the transformer or removed from the window of the transformer in the field with very simple tools. This adaptor permits the extension of the range of use of a conventional or standard through-type current transformer to another range of applications from which the transformer was originally designed.

Since numerous changes may be made in the above described apparatus and different embodiments of theinvention may be made without departing from the spirit thereof, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative, and not in a limiting sense.

l claim:

1. An adaptor mounted in the window of a throughtype current transformer for adapting said transformer for mounting on a spade type terminal, said transformer having a casing comprising an outer wall, an inner wall defining a window and a pair of spaced side walls connected to the outer wall and the inner wall, said adaptor comprising a body member, said body member having a pair of spaced spring members attached thereto, said adaptor being positioned in the window of the transformer with each of .said spring members engaging a separate one of said spaced side walls of said transformer casing at a point outside of the window of said transformer to hold said adaptor in the window of the transformer, said adaptor having a slot therein for receiving a spade type terminal.

adaptors positioned in said window at opposite sides thereof, each of said adaptors comprising a body member having a slot therein, each of said adaptors having a pair of spring members attached thereto, said spring members of each of said adaptors being spaced so as to engage opposite sides of said transformer casing outside of said window, the slots in said adaptors being opposite each other to receive the edges of a spade type terminal. 

1. An adaptor mounted in the window of a through-type current transformer for adapting said transformer for mounting on a spade type terminal, said transformer having a casing comprising an outer wall, an inner wall defining a window and a pair of spaced side walls connected to the outer wall and the inner wall, said adaptor comprising a body member, said body member having a pair of spaced spring members attached thereto, said adaptor being positioned in the window of the transformer with each of said spring members engaging a separate one of said spaced side walls of said transformer casing at a point outside of the window of said transformer to hold said adaptor in the window of the transformer, said adaptor having a slot therein for receiving a spade type terminal.
 2. The apparatus of claim 1 wherein ribs are provided on opposite side walls inside said slot in said adaptor.
 3. The apparatus of claim 1 wherein ribs are provided on only one side wall inside said slot in said adaptor.
 4. The apparatus of claim 1 wherein hook members for engaging the side walls of said casing outside the window are provided on each of said spring members.
 5. A through-type current transformer having a window therein, said transformer having a casing having opposite side walls adjacent said window, a pair of adaptors positioned in said window at opposite sides thereof, each of said adaptors comprising a body member having a slot therein, each of said adaptors having a pair of spring members attached thereto, said spring members of each of said adaptors being spaced so as to engage opposite sides of said transformer casing outside of said window, the slots in said adaptors being opposite each other to receive the edges of a spade type terminal. 